Watch how cement-free concrete bends
S. Himmelstein | March 05, 2020A sustainable alternative to traditional concrete, the most widely used material worldwide, has been formulated by researchers from Swinburne University of Technology, Australia, and Nanyang Technological University, 
The cement-free composite bends under load. Source: Swinburne University of TechnologySingapore.
Synthesized with coal fly ash and other industrial wastes, the new geopolymer composite is as strong as common concrete but possesses some flexibility: High tensile strength lets the material bend under strain, making it suitable for construction in areas prone to earthquakes and other natural disasters. The composite is cured at ambient temperature and eliminates the need to use cement, which translates into 76% less carbon emissions and 36% lower energy consumption compared with conventional concrete manufacture.
Short polymeric fibers in the concrete mixture are largely responsible for its ductile properties, allowing the material to sustain multiple hair-sized cracks under tension or bend without breaking or shattering. Laboratory tests demonstrated the new concrete to be 400 times more bendable than conventional concrete.
So the polymer slab bends but it remains deformed after the pressure is relieved. Can this be a good thing to have a polymer acting like a metal? What effect would the deformation have on a wall or bridge, not a good result I think.
In reply to #1
<...deformation...po
One wouldn't design such a structure using this material in the domain where it would do this, in the same way as one wouldn't craft the proverbial tea pot out of chocolate.
In reply to #2
isitVery cool - it should have a large number of very useful applications with this ability to withstand catastrophic failure.
When sustainability is being assessed, it is great that it uses a previous waste material and requires considerably less additional carbon emission than manufacturing virgin concrete; however, I wonder about the ability to recover/reuse/recycl
Often, we engineers fail to design for complete life cycle environmental impact because generally end of life costs are not born by original manufacturers.
Business interests don't impose this constraint on design and too often are in opposition, particularly in the absence of strong social policy constraint.
Would a bowed bridge deck not fall from it's piers?
Perhaps the applications for this are specific, such as building slabs or in the case of a bridge; would be more akin to a suspension or truss design.
It is very interesting to find the trifecta.... cheaper, stronger and greener.
But for longer spans, how could this work ?
Seems like it would work fine considering that a structure made of cement would be fractured (instead of bent). That's generally a more deisreable failure mode.
Concrete:
Tensile strength - σ : 2 - 5 MPa (300 - 700 psi)
https://www.engineer
Strain-hardening geopolymer composite (SHGC):
Tens. Str.: 4 MPa
https://www.scienced
In reply to #6
**Bending being more desireable than fracture.
At any point where the SHGC would bend, concrete would be fractured...